Easy Overnight Slow Cooker Breakfast Casserole (Ready When You Wake Up!)

Wake up to a hot, hearty breakfast without morning cooking stress
Prep in just 15 minutes the night before for hassle-free mornings
Customize with your favorite breakfast meats and cheeses
Perfect for busy families needing a well-balanced breakfast spread

Never Struggle with Morning Meal Prep Again

Morning chaos making breakfast impossible? We’ve all been there.

This slow cooker breakfast casserole solves your morning rush problems. Prep it the night before, set your slow cooker, and wake up to a hot, delicious breakfast. No morning cooking required!

With hash browns, eggs, and savory breakfast meats, this hearty breakfast casserole delivers a complete meal with minimal effort. It’s perfect for busy weekdays, weekend family brunches, or holiday mornings when you’d rather spend time with loved ones than in the kitchen.

Nutrition Information

Nutrient	Amount per Serving
Calories	385
Protein	23g
Carbohydrates	22g
Fat	24g
Fiber	2g
Sodium	780mg

Nutrition values based on recipe using regular pork sausage and full-fat cheese. Values will vary with substitutions.

Equipment & Ingredients

Kitchen Tools

Tool	Purpose
6-quart slow cooker	Main cooking vessel
Large mixing bowl	For whisking eggs and milk
Skillet	For browning meat (if not using pre-cooked)
Measuring cups and spoons	For accurate measurements
Whisk	For beating eggs
Sharp knife	For chopping vegetables
Cutting board	For prep work
Slow cooker liner (optional)	For easier cleanup

Ingredients (Serves 4)

Ingredient	Amount	Notes
Frozen hash browns	3 cups	Thawed and patted dry
Breakfast sausage	8 oz	Cooked and crumbled
Sharp cheddar cheese	1 cup	Shredded
Eggs	6 large	Room temperature for best results
Milk	1/2 cup	Whole milk recommended
Bell pepper	1/2	Diced small
Onion	1/4 cup	Finely diced
Salt	1/2 tsp	To taste
Black pepper	1/4 tsp	To taste
Garlic powder	1/4 tsp	Adds depth of flavor
Nonstick cooking spray	As needed	For coating slow cooker

Optional Substitutions

Meat options: Replace sausage with cooked turkey sausage, turkey bacon, ham, or omit for vegetarian
Cheese varieties: Swap cheddar for pepper jack, mozzarella, or a cheese blend
Potato alternatives: Use diced fresh potatoes instead of frozen hash browns
Milk substitutes: Almond milk or low-fat milk work well
Egg options: Egg whites or low-fat egg substitutes can reduce calories

Detailed Beginner-Friendly Instructions

Preparation Phase (Total time: 8 hours, 15 minutes)

Prep time: 15 minutes
Cook time: 7-8 hours on LOW or 3-4 hours on HIGH
Total time: 8 hours and 15 minutes (mostly hands-off)

Step-by-Step Instructions

Step 1: Prepare Your Ingredients

Take out all ingredients: Place everything on your counter so you can see what you’re working with.

Check expiration dates on all ingredients before starting.
Take eggs out of the refrigerator 20-30 minutes before using for best results.

Thaw frozen hash browns:

Option 1: Place hash browns in refrigerator the night before (8+ hours).
Option 2: Use microwave defrost function (follow package instructions).
Option 3: Place sealed bag in cold water for 30-45 minutes.

Remove excess moisture from hash browns:

Spread thawed hash browns on a clean kitchen towel or paper towels.
Press gently with another towel to absorb moisture.
This prevents a watery casserole and is extremely important – don’t skip this step!

Prepare vegetables:

Wash bell pepper thoroughly under cold running water.
Cut bell pepper in half and remove seeds and white membrane using a spoon.
Place pepper cut-side down on cutting board for stability.
Cut into thin strips, then rotate and cut into small dice (about 1/4-inch pieces).
For onion, cut off both ends and remove outer skin.
Cut in half from top to bottom, place flat side down, and slice into thin pieces.
Rotate and cut crosswise into small dice.

Step 2: Cook the Meat (If Using Raw Sausage)

Prepare skillet:

Place skillet on stove over medium heat.
Allow pan to heat for 1-2 minutes before adding meat.

Cook sausage:

Remove sausage from packaging.
Add to hot skillet (no need to add oil as sausage has enough fat).
Break sausage into small pieces using a wooden spoon or spatula.
Stir occasionally to ensure even cooking.
Cook for 5-7 minutes until no pink remains.
The internal temperature should reach 160°F if you have a meat thermometer.

Drain excess fat:

Turn off heat once meat is fully cooked.
Line a plate with 2-3 paper towels.
Using a slotted spoon, transfer cooked sausage to paper towels.
Press lightly with additional paper towels to remove more grease if needed.
Let cool for 5 minutes before handling further.

Step 3: Prepare the Egg Mixture

Break eggs:

Crack each egg individually into a small bowl first to check for shell fragments.
Transfer each egg to the large mixing bowl after checking.
This method prevents having to discard all eggs if one is bad.

Add liquid and seasonings:

Measure 1/2 cup milk and add to eggs.
Add 1/2 teaspoon salt (about a small pinch between three fingers).
Add 1/4 teaspoon black pepper (about half of a small pinch).
Add 1/4 teaspoon garlic powder (same amount as pepper).

Mix thoroughly:

Using a whisk, beat eggs in a circular motion for 30-45 seconds.
The mixture should be fully combined with no visible egg white streaks.
It should look slightly frothy on top.
Tip: Hold the bowl firmly with one hand while whisking with the other to prevent it from spinning.

Step 4: Prepare the Slow Cooker

Coat slow cooker:

If using a slow cooker liner, insert it now, smoothing out any wrinkles.
If not using a liner, spray the inside of your slow cooker thoroughly with nonstick cooking spray.
Be sure to coat the sides about 2 inches up from the bottom as well.

Step 5: Layer Ingredients

First layer – Hash browns:

Spread the dried hash browns evenly across the bottom of the slow cooker.
Use the back of a spoon to gently press them down to create an even base.
Make sure they reach all the way to the edges.

Second layer – First cheese portion:

Sprinkle half of the shredded cheese (1/2 cup) evenly over the hash browns.
Distribute it all the way to the edges for even melting.

Third layer – Sausage:

Distribute the cooked sausage crumbles evenly over the cheese layer.
Break up any large chunks with your fingers for more even cooking.

Fourth layer – Vegetables:

Sprinkle diced bell peppers and onions evenly over the sausage.
Try to distribute them evenly so no one gets a bite with too many vegetables.

Fifth layer – Egg mixture:

Slowly pour the egg mixture over all the ingredients.
Pour in a circular pattern starting from the outside and moving in.
If needed, use a fork to gently press ingredients down so egg mixture can reach the bottom.
The egg mixture should just barely cover all ingredients.

Final layer – Remaining cheese:

Sprinkle the remaining 1/2 cup of cheese on top of everything.
Make sure to cover the entire surface for a beautiful golden top.

Step 6: Cook the Casserole

Cover the slow cooker:

Place the lid securely on your slow cooker.
Make sure it’s properly seated with no gaps.

Set cooking temperature and time:

For overnight cooking: Set to LOW for 7-8 hours.
For same-day cooking: Set to HIGH for 3-4 hours.
Note the start time so you know when it will be finished.

Leave it alone:

Resist the urge to open the lid during cooking!
Each time you lift the lid, you lose 15-20 minutes of cooking time as heat escapes.
No stirring is necessary or recommended.

Check for doneness (at the minimum cooking time):

Carefully remove lid, tilting it away from you to avoid steam burns.
Insert a knife or toothpick into the center of the casserole.
It should come out clean with no raw egg mixture.
The edges should be slightly golden, and the center should be set (not jiggly).
The internal temperature should reach 160°F if using a food thermometer.

Step 7: Finish and Serve

Turn off slow cooker:

Once fully cooked, turn off the slow cooker.
If your model doesn’t have an automatic “keep warm” setting, unplug it.

Let it rest:

Allow the casserole to rest for 10 minutes before serving.
This helps it set up and makes it easier to cut into portions.

Slice and serve:

Use a knife to cut the casserole into 4 equal portions directly in the slow cooker.
A rubber spatula works best for removing each portion.
Lift carefully, supporting the bottom of each piece.

Add optional toppings:

Set out optional toppings like:
- Fresh salsa
- Sliced green onions
- Sour cream
- Hot sauce
- Fresh herbs (chopped parsley or chives)
Let each person customize their own portion.

Overnight Slow Cooker Breakfast Casserole

Troubleshooting Common Issues

Problem: Casserole is too watery

Solution: Ensure hash browns are thoroughly thawed and patted dry before using. Excess moisture from vegetables or potatoes can make the casserole watery.

Problem: Edges are burnt but center is undercooked

Solution: Your slow cooker might heat unevenly. Next time, rotate the insert halfway through cooking if possible, or try cooking on LOW for a longer time instead of HIGH.

Problem: Egg mixture is overcooked or rubbery

Solution: Your slow cooker might run hot. Check doneness earlier than the recipe suggests, and reduce cooking time in future batches.

Problem: Casserole sticks to slow cooker

Solution: Use more cooking spray next time or invest in slow cooker liners for easy cleanup.

Variations & Substitutions

Mexican-Style:

Add 1/2 cup black beans
Use pepper jack cheese instead of cheddar
Include 1/4 cup diced green chilies
Serve with avocado slices and salsa

Mediterranean:

Substitute feta cheese for cheddar
Add 1/4 cup chopped spinach
Include 2 tablespoons diced sun-dried tomatoes
Add 1 teaspoon dried oregano to egg mixture

Meat Lover’s:

Use a combination of sausage and bacon
Add 1/4 cup diced ham
Increase cheese to 1 1/2 cups

Vegetarian:

Omit meat
Add 1 cup mixed sautéed vegetables (mushrooms, zucchini, spinach)
Include 1/4 teaspoon smoked paprika for flavor

Storage & Reheating

Refrigerator Storage:

Cool completely before storing.
Portion into containers for easy reheating.
Refrigerate for up to 3 days in airtight containers.

Freezer Storage:

Freeze individual portions for up to 2 months.
Wrap tightly in plastic wrap and place in freezer bags.
Label with date and contents.

Reheating Instructions:

Microwave: Heat refrigerated portions for 1-2 minutes or until hot.
Oven: Warm at 350°F for 10-15 minutes.
From frozen: Thaw overnight in refrigerator before reheating, or microwave on defrost setting first.

Safety Notes & Tips

Food Safety:

Never leave egg mixture at room temperature for more than 2 hours.
Cook to minimum internal temperature of 160°F to ensure eggs are safe to eat.
Discard leftovers after 3 days in refrigerator.

Cooking Tips:

Prep ingredients the night before for a truly hands-off morning.
Don’t fill slow cooker more than 2/3 full for even cooking.
Use freshly grated cheese instead of pre-grated for better melting.
Check new slow cookers earlier than recipe states as newer models often cook hotter.

Time-Saving Tricks:

Use pre-cooked breakfast meats to skip the browning step.
Prep and store dry and wet ingredients separately the night before.
Chop extra vegetables when meal prepping for the week and freeze in portions for future casseroles.

Serving Suggestions:

Pair with fresh fruit for a complete breakfast.
Serve with sourdough toast for added texture.
Set up a toppings bar with salsa, sour cream, and hot sauce for customization.

This slow cooker breakfast casserole recipe makes mornings stress-free while delivering a hearty, homemade meal. Perfect for busy families, weekend gatherings, or holiday mornings when you want to enjoy your time rather than standing over the stove.